Displaying publications 1 - 20 of 34 in total

Abstract:
Sort:
  1. Salhin A, Abdul Razak N, Rahman IA
    PMID: 21583090 DOI: 10.1107/S1600536809016225
    The title compound, C(14)H(11)BrN(4)O(4), comprises two crystallographically independent mol-ecules (A and B) in the asymmetric unit. In mol-ecule B, intra-molecular bifurcated N-H⋯O and N-H⋯Br hydrogen bonds and in mol-ecule A, an intra-molecular N-H⋯O hydrogen bond generate S(6) ring motifs. The dihedral angle between the phenyl and benzene rings is 5.44 (6) in mol-ecule A and 7.63 (6)° in mol-ecule B. The ortho- and meta-nitro substituents make dihedral angles of 6.67 (15) and 2.26 (15)° to the attached benzene ring in mol-ecule A and 6.37 (17) and 5.81 (16)° in mol-ecule B. The Br atom in mol-ecule B is disordered over two positions with a refined site-occupancy ratio of 0.61 (3):0.39 (3). Inter-esting features of the crystal structure are the short Br⋯N [3.257 (3)-3.294 (4) Å], Br⋯O [3.279 (3)-3.307 (4) Å] and O⋯O [2.9319 (16)-2.9995 (16) Å] contacts, which are shorter than the sum of the van der Waals radii of these atoms. The crystal structure is further stabilized by inter-molecular C-H⋯O and π-π inter-actions [centroid-centroid distances = 3.6643 (8)-3.8514 (8) Å].
  2. Abd Razak NA, Abu Osman NA, Kamyab M, Wan Abas WA, Gholizadeh H
    Am J Phys Med Rehabil, 2014 May;93(5):437-44.
    PMID: 24429510 DOI: 10.1097/PHM.0b013e3182a51fc2
    This report compares wrist supination and pronation and flexion and extension movements with the common body-powered prosthesis and a new biomechatronics prosthesis with regard to patient satisfaction and problems experienced with the prosthesis. Fifteen subjects with traumatic transradial amputation who used both prosthetic systems participated in this study. Each subject completed two questionnaires to evaluate their satisfaction and problems experienced with the two prosthetic systems. Satisfaction and problems with the prosthetic's wrist movements were analyzed in terms of the following: supination and pronation; flexion and extension; appearance; sweating; wounds; pain; irritation; pistoning; smell; sound; durability; and the abilities to open a door, hold a cup, and pick up or place objects. This study revealed that the respondents were more satisfied with the biomechatronics wrist prosthesis with regard to supination and pronation, flexion and extension, pain, and the ability to open a door. However, satisfaction with the prosthesis showed no significant differences in terms of sweating, wounds, irritation, pistoning, smell, sound, and durability. The abilities to hold a cup and pick up or place an object were significantly better with the body-powered prosthesis. The results of the survey suggest that satisfaction and problems with wrist movements in persons with transradial amputation can be improved with a biomechatronics wrist prosthesis compared with the common body-powered prosthesis.
  3. Razak NN, Annuar MS
    Appl Biochem Biotechnol, 2014 Mar;172(6):2932-44.
    PMID: 24464534 DOI: 10.1007/s12010-014-0731-7
    Free laccase and fungal biomass from white-rot fungi were compared in the thermokinetics study of the laccase-catalyzed decolorization of an azo dye, i.e., Trypan Blue. The decolorization in both systems followed a first-order kinetics. The apparent first-order rate constant, k1', value increases with temperature. Apparent activation energy of decolorization was similar for both systems at ∼ 22 kJ mol(-1), while energy for laccase inactivation was 18 kJ mol(-1). Although both systems were endothermic, fungal biomass showed higher enthalpy, entropy, and Gibbs free energy changes for the decolorization compared to free laccase. On the other hand, free laccase showed reaction spontaneity over a wider range of temperature (ΔT = 40 K) as opposed to fungal biomass (ΔT = 15 K). Comparison of entropy change (ΔS) values indicated metabolism of the dye by the biomass.
  4. Abdul Razak N, Azhar ZI, Baharuddin IH, Ismail Z, Mohd Azman ZA, Abdul Manap SA, et al.
    Asian Pac J Cancer Prev, 2024 Feb 01;25(2):379-391.
    PMID: 38415522 DOI: 10.31557/APJCP.2024.25.2.379
    INTRODUCTION: Early diagnostic and treatment advances have resulted in prolonged cancer survivorship. Therefore, exercise intervention in survivorship management is essential for enhancing cancer survivors' health-related quality of life (HRQoL).

    OBJECTIVE: The systematic review and meta-analysis in this study aimed to explore the effect of exercise intervention on health-related quality of life of colorectal cancer survivors.

    METHODS: The current study followed guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 (PRISMA 2020) to identify relevant literature. Comprehensive searches were conducted using EBSCOhost, Web of Science (WOS), Scopus, Science Direct, and PubMed. The inclusion criteria included are randomised control trials studies written in English, with no restrictions for the time of publication that reported the effects of exercise intervention on health-related quality of live among colorectal cancer survivors. Meta-analysis was conducted by pooling the mean and standard deviation of post-intervention scores across randomised control trial studies using a random effects model.

    RESULT: A total of 467 articles were identified but only seven articles were randomised control trials (RCT) (n = 7) with PEDro scores ranging from 6 to 9 showing good internal validity were included in the review. The results of the meta-analysis of pooled data from six RCTs studies on HRQoL showed no significant effect of exercise intervention on HRQoL in the intervention group compared to control group [SMD = 0.25; 95% CI; -0.0, 0.51; Z = 1.88; p = 0.06; I2 = 30.8%].

    CONCLUSION: This meta-analysis provides key insights into the effect of exercise on the health-related quality of life (HRQoL) of colorectal cancer (CRC) survivors. Therefore, more experimental studies should be carried out with rigorous methodology to evaluate the effectiveness of exercise interventions before it is recommended as a routine activity in post-treatment management for CRC survivors.

  5. Hasan MS, Abdul Razak N, Yip HW, Lee ZY, Chan CYW, Kwan MK, et al.
    BMC Anesthesiol, 2023 May 24;23(1):177.
    PMID: 37226107 DOI: 10.1186/s12871-023-02127-8
    BACKGROUND: The liberal use of remifentanil in spine surgery has been associated with an increased incidence of postoperative hyperalgesia. Nevertheless, controversies remain as the existing evidence is inconclusive to determine the relationship between remifentanil use and the development of opioid-induced hyperalgesia. We hypothesized that intraoperative infusion of higher dose remifentanil during scoliosis surgery is associated with postoperative hyperalgesia, manifesting clinically as greater postoperative morphine consumption and pain scores.

    METHODS: Ninety-seven patients with adolescent idiopathic scoliosis (AIS) who underwent posterior spinal fusion surgery at a single tertiary institution from March 2019 until June 2020 were enrolled in this retrospective study. Anesthesia was maintained using a target-controlled infusion of remifentanil combined with volatile anesthetic desflurane in 92 patients, while five patients received it as part of total intravenous anesthesia. Intravenous ketamine, paracetamol, and fentanyl were administered as multimodal analgesia. All patients received patient-controlled analgesia (PCA) morphine postoperatively. Pain scores at rest and on movement, assessed using the numerical rating scale, and the cumulative PCA morphine consumption were collected at a six-hourly interval for up to 48 h. According to the median intraoperative remifentanil dose usage of 0.215 µg/kg/min, patients were divided into two groups: low dose and high dose group.

    RESULTS: There were no significant differences in the pain score and cumulative PCA morphine consumption between the low and high dose remifentanil group. The mean duration of remifentanil infusion was 134.9 ± 22.0 and 123.4 ± 23.7 min, respectively.

    CONCLUSION: Intraoperative use of remifentanil as an adjuvant in AIS patients undergoing posterior spinal fusion surgery was not associated with postoperative hyperalgesia.

  6. Kok EY, Kaur S, Mohd Shukri NH, Abdul Razak N, Takahashi M
    BMC Pregnancy Childbirth, 2024 Mar 23;24(1):217.
    PMID: 38521925 DOI: 10.1186/s12884-024-06403-4
    BACKGROUND: During pregnancy, physiological changes can affect eating and sleeping habits, which may eventually have negative consequences for maternal and foetal health. To better understand these changes, it is essential to develop a reliable questionnaire that addresses lifestyle habits such as snacking and daytime napping. This study aimed to determine the validity and reliability of the Chrononutrition Profile Questionnaire-Pregnancy (CPQ-P).

    METHODS: A total of 399 women in their second and third trimester of pregnancy were recruited from government maternal and child health clinics in Kuala Lumpur and Putrajaya and completed a self-administered online questionnaire. Content validity was conducted with an expert panel consisting of 4 members. Confirmatory factor analysis (CFA) using maximum likelihood was conducted to determine the construct validity. Internal consistency was determined by Cronbach's alpha coefficient (CAC), while the test-retest reliability was conducted using intraclass correlation coefficient (ICC).

    RESULTS: The questionnaire had an appropriate content validity index of 0.91. The CPQ-P consists of 22 items, measuring 5 constructs, including morning chrono-habits, sleeping habits, evening eating, temporal eating, and pregnancy symptoms. The factor model showed good fit with χ2/df = 2.486, GFI = 0.893, CFI = 0.912, and RMSEA = 0.065. The 22 items in CPQ-P showed fair to excellent test-retest reliability (ICC: 0.42 to 0.98). The 5 constructs in CPQ-P were found to have a good to excellent internal consistency (α = 0.612-0.963).

    CONCLUSIONS: The CPQ-P is a valid and reliable tool for assessing lifestyle habits during pregnancy. The questionnaire can be used to identify areas where pregnant women may need additional support or intervention to adopt healthy behaviours and reduce the risk of adverse maternal and foetal outcomes.

    TRIAL REGISTRATION: NCT05700136 (clinicaltrials.gov). Trial registration date: 26/01/2023.

  7. Jan Mohamed HJ, Loy SL, Mohd Taib MN, Karim NA, Tan SY, Appukutty M, et al.
    BMC Public Health, 2015;15:1322.
    PMID: 26718818 DOI: 10.1186/s12889-015-2666-5
    The consumption of beverages contributes to diet quality and overall nutrition. Studies on malted drinks, one of the widely consumed beverage choices among children in Asia, however, have received limited attention. This study aimed to examine the prevalence of malted drink consumption and explored associations of sociodemographic characteristics, nutrient intakes, weight status and physical activity levels with malted drink consumption among primary school children in Malaysia.
  8. Gholizadeh H, Abu Osman NA, Eshraghi A, Ali S, Razak NA
    Clin Biomech (Bristol, Avon), 2014 Jan;29(1):87-97.
    PMID: 24315710 DOI: 10.1016/j.clinbiomech.2013.10.013
    Today a number of prosthetic suspension systems are available for transtibial amputees. Consideration of an appropriate suspension system can ensure that amputee's functional needs are satisfied. The higher the insight to suspension systems, the easier would be the selection for prosthetists. This review attempted to find scientific evidence pertaining to various transtibial suspension systems to provide selection criteria for clinicians.
  9. Saperi BS, Ramli R, Ahmed Z, Muhd Nur A, Ibrahim MI, Rashdi MF, et al.
    Clinicoecon Outcomes Res, 2017;9:107-113.
    PMID: 28223831 DOI: 10.2147/CEOR.S119910
    OBJECTIVE: Facial injury (FI) may occur in isolation or in association with injuries to other parts of the body (facial and other injury [FOI]). The objective of this study was to determine the direct treatment costs incurred during the management of facial trauma.

    MATERIALS AND METHODS: A prospective cohort study on treatment cost for FIs and FOIs due to road-traffic crashes in two university hospitals in Malaysia was conducted from July 2010 to June 2011. The patients were recruited from emergency departments and reviewed after 6 months from the date of initial treatment. Direct cost analysis, comparison of cost and length of hospital stay, and Injury Severity Score (ISS) were performed.

    RESULTS: A total of 190 patients were enrolled in the study, of whom 83 (43.7%) had FI only, and 107 (56.3%) had FOI. The mean ISS was 5.4. The mean length of stay and costs for patients with FI only were 5.8 days with a total cost of US$1,261.96, whereas patients with FOI were admitted for 7.8 days with a total cost of US$1,716.47. Costs doubled if the treatment was performed under general anesthesia compared to local anesthesia.

    CONCLUSION: Treatment of FI and FOI imposes a financial burden on the health care system in Malaysia.

  10. Abdul Razak N, Nordin R, Abd Rahman N, Ramli R
    Dent Traumatol, 2017 Oct;33(5):400-405.
    PMID: 28649703 DOI: 10.1111/edt.12355
    BACKGROUND/AIMS: The association between facial injury characteristics and mild traumatic brain injury (mTBI) is unclear. The aim of this study was to determine the association between facial injury characteristics and mTBI.

    METHODS: A retrospective review utilizing patients' medical records at the Universiti Kebangsaan Malaysia Medical Centre (UKMMC), Kuala Lumpur, Malaysia, was performed. Records of subjects with a history of facial trauma from 1 April 2012 to 31 December 2012 were selected. Various levels and surgical speciality records were reviewed to ascertain the diagnoses of facial injuries and mTBI.

    RESULTS: A total of 348 medical records with the diagnosis of facial injuries were included. The prevalence of mTBI among these patients was 41.4% (95% CI 36.2-46.6). The majority of the patients with mTBI were in the age group of 18-25 years old. Patients with or without facial lacerations that were located on the lower face had a significant association with mTBI, P=.001, compared to other types of soft tissue injury. In addition, a statistically significant association was observed between facial fractures occurring to the middle face and mTBI, P=.018. Pearson chi-square test also showed statistically significant association between the severity of facial injuries and mTBI, P=.018.

    CONCLUSIONS: Mild traumatic brain injury should be suspected in patients with facial injuries and particularly those with lower face lacerations, midface fractures, moderate to severe facial injury and presence of multiple injuries.

  11. Abd Razak NA, Abu Osman NA, Wan Abas WA
    Disabil Rehabil Assist Technol, 2013 May;8(3):255-60.
    PMID: 22830946 DOI: 10.3109/17483107.2012.704654
    This study examined the kinematic differences between a body-powered prosthesis and a biomechatronics prosthesis as a transradial amputee performed activities that involve flexion/extension and supination/pronation of the wrist.
  12. Abd Razak N, Yeap SK, Alitheen NB, Ho WY, Yong CY, Tan SW, et al.
    Integr Cancer Ther, 2020 8 25;19:1534735420935625.
    PMID: 32830560 DOI: 10.1177/1534735420935625
    Eupatorin is a polymethoxy flavone extracted from Orthosiphon stamineus and was reported to exhibit cytotoxic effects on several cancer cell lines. However, its effect as an anti-breast cancer agent in vivo has yet to be determined. This study aims to elucidate the potential of eupatorin as an anti-breast cancer agent in vivo using 4T1 challenged BALB/c mice model. In this article, BALB/c mice (20-22 g) challenged with 4T1 cells were treated with 5 mg/kg or 20 mg/kg eupatorin, while the untreated and healthy mice were fed with olive oil (vehicle) via oral gavage. After 28 days of experiment, the mice were sacrificed and blood was collected for serum cytokine assay, while tumors were harvested to extract RNA and protein for gene expression assay and hematoxylin-eosin staining. Organs such as spleen and lung were harvested for immune suppression and clonogenic assay, respectively. Eupatorin (20 mg/kg) was effective in delaying the tumor development and reducing metastasis to the lung compared with the untreated mice. Eupatorin (20 mg/kg) also enhanced the immunity as the population of NK1.1+ and CD8+ in the splenocytes and the serum interferon-γ were increased. Concurrently, eupatorin treatment also has downregulated the expression of pro-inflammatory and metastatic related genes (IL-1β. MMP9, TNF-α, and NF-κB). Thus, this study demonstrated that eupatorin at the highest dosage of 20 mg/kg body weight was effective in delaying the 4T1-induced breast tumor growth in the animal model.
  13. Arsad N, Abd Razak N, Omar MH, Shafiee MN, Kalok A, Cheah FC, et al.
    PMID: 35564596 DOI: 10.3390/ijerph19095201
    This exploratory study aimed to evaluate the effects of antenatal corticosteroids in singleton pregnancies of Asian women prior to elective cesarean section (CS) at early term on neonatal respiratory outcomes.

    METHODS: This is a pilot and pragmatic randomized trial conducted at a university hospital in Malaysia. Women with singleton pregnancies planned for elective CS between 37+0 and 38+6 weeks gestation were randomly allocated into the intervention group, where they received two doses of IM dexamethasone 12 mg of 12 h apart, 24 h prior to surgery OR into the standard care, control group, and both groups received the normal routine antenatal care. The primary outcome measures were neonatal respiratory illnesses, NICU admission and length of stay.

    RESULTS: A total of 189 patients were recruited, 93 women in the intervention group and 96 as controls. Between the steroid and control groups, the mean gestation at CS was similar, 266.1 ± 3.2 days (38 weeks) vs. 265.8 ± 4.0 days (37+6 weeks), p = 0.53. The mean birthweight of infants was 3.06 ± 0.41 kg vs. 3.04 ± 0.37 kg, p = 0.71. Infants with respiratory morbidities were primarily due to transient tachypnea of newborn (9.7% vs. 6.3%), and congenital pneumonia (1.1% vs. 3.1%) but none had respiratory distress syndrome. Only four infants required NICU admission (2.2% vs. 3.1%, p = 0.63). Their average length of stay was not statistically different; 3.5 ± 2.1 days vs. 5.7 ± 1.5 days, p = 0.27.

    CONCLUSIONS: Elective CS at early term before 39 weeks was associated with a modest overall incidence of neonatal respiratory illness (10.1%) in this Asian population. Antenatal dexamethasone did not diminish infants needing respiratory support, NICU admission and length of stay.

  14. Juhan N, Abd Razak N, Zubairi YZ, Khattak MN, Naing NN
    Iran J Public Health, 2013 Sep;42(9):980-7.
    PMID: 26175969
    BACKGROUND: Cervical cancer is the third most common cancer among women in Malaysia. The objective of this study was to estimate the effect of explanatory variables on survival time of cervical cancer patients receiving treatment at a hospital in Malaysia.

    METHODS: In this retrospective record review study, cervical cancer data obtained from Hospital UniversitiSains Malaysia (HUSM) was analysed. The data comprises of 120 patients who had been diagnosed as cervical cancer between 1(st) July 1995 and 30(th) June 2007, and obtained treatment from the hospital. The outcome variable was survival time (in months) from cervical cancer diagnosis to death. A stratified Weibull model was applied to study the effect of explanatory variable on survival time when there was time-dependent covariate in the model.

    RESULTS: Stage of disease and metastases were important prognostic variables. However, metastasis had been stratified because this variable did not satisfy the proportional hazard assumption. In without metastasis stratum, patients who were diagnosed at stage III & IV are at 2.30 times the risk of death as those in stage I & II. Meanwhile, in with metastasis stratum, patients in stage III & IV group had 3.53 times the hazard faced by patients in stage I & II.

    CONCLUSION: The prognosis of cervical cancer patients was dependent upon the stage at diagnosis, after the stratification of the metastasis variable. A poorer prognosis on survival was observed for patients in stage III & IV than those in stage I & II.

  15. Hashim NA, Abd Razak NA, Gholizadeh H, Abu Osman NA
    JMIR Serious Games, 2021 Feb 04;9(1):e17017.
    PMID: 33538698 DOI: 10.2196/17017
    BACKGROUND: Brain plasticity is an important factor in prosthesis usage. This plasticity helps with brain adaptation to learn new movement and coordination patterns needed to control a prosthetic hand. It can be achieved through repetitive muscle training that is usually very exhausting and often results in considerable reduction in patient motivation. Previous studies have shown that a playful concept in rehabilitation can increase patient engagement and perseverance.

    OBJECTIVE: This study investigated whether the inclusion of video games in the upper limb amputee rehabilitation protocol could have a beneficial impact for muscle preparation, coordination, and patient motivation among individuals who have undergone transradial upper limb amputation.

    METHODS: Ten participants, including five amputee participants and five able-bodied participants, were enrolled in 10 1-hour sessions within a 4-week rehabilitation program. In order to investigate the effects of the rehabilitation protocol used in this study, virtual reality box and block tests and electromyography (EMG) assessments were performed. Maximum voluntary contraction was measured before, immediately after, and 2 days after interacting with four different EMG-controlled video games. Participant motivation was assessed with the Intrinsic Motivation Inventory (IMI) questionnaire and user evaluation survey.

    RESULTS: Survey analysis showed that muscle strength and coordination increased at the end of training for all the participants. The results of Pearson correlation analysis indicated that there was a significant positive association between the training period and the box and block test score (r8=0.95, P

  16. Yahia A, Szlávecz Á, Knopp JL, Norfiza Abdul Razak N, Abu Samah A, Shaw G, et al.
    PMID: 34078114 DOI: 10.1177/19322968211018260
    BACKGROUND: Critically ill ICU patients frequently experience acute insulin resistance and increased endogenous glucose production, manifesting as stress-induced hyperglycemia and hyperinsulinemia. STAR (Stochastic TARgeted) is a glycemic control protocol, which directly manages inter- and intra- patient variability using model-based insulin sensitivity (SI). The model behind STAR assumes a population constant for endogenous glucose production (EGP), which is not otherwise identifiable.

    OBJECTIVE: This study analyses the effect of estimating EGP for ICU patients with very low SI (severe insulin resistance) and its impact on identified, model-based insulin sensitivity identification, modeling accuracy, and model-based glycemic clinical control.

    METHODS: Using clinical data from 717 STAR patients in 3 independent cohorts (Hungary, New Zealand, and Malaysia), insulin sensitivity, time of insulin resistance, and EGP values are analyzed. A method is presented to estimate EGP in the presence of non-physiologically low SI. Performance is assessed via model accuracy.

    RESULTS: Results show 22%-62% of patients experience 1+ episodes of severe insulin resistance, representing 0.87%-9.00% of hours. Episodes primarily occur in the first 24 h, matching clinical expectations. The Malaysian cohort is most affected. In this subset of hours, constant model-based EGP values can bias identified SI and increase blood glucose (BG) fitting error. Using the EGP estimation method presented in these constrained hours significantly reduced BG fitting errors.

    CONCLUSIONS: Patients early in ICU stay may have significantly increased EGP. Increasing modeled EGP in model-based glycemic control can improve control accuracy in these hours. The results provide new insight into the frequency and level of significantly increased EGP in critical illness.

  17. Shafiee MN, Razak N, Ahmad MF, Abd Aziz N, Adeeb N
    J Obstet Gynaecol, 2021 Feb;41(2):285-289.
    PMID: 33258710 DOI: 10.1080/01443615.2020.1819210
    Endometrial cancer (EC) has been found to have a strong association with overweight and obesity. The aim of this study was to evaluate the link between metabolic syndrome and EC among patients. A total of 119 patients with histologically confirmed EC were recruited. About 102 cases of endometrioid carcinoma (Type I) and serous (n = 7), clear cell (n = 3) and carcinosarcoma (n = 7) were the Type II. Metabolic syndrome was significantly associated with increased risk of Type I EC (OR = 3.43, 95% CI = 1.12-10.46, p  .05). Metabolic syndrome was positively associated with an increased risk of Type I EC with obesity being the most influential risk factor.Impact statementWhat already known on this subject? Endometrial cancer (EC) is one of the most prevalent cancers worldwide and have a strong association with overweight and obesity of at least 40%, but there is conflicting evidence of an association of EC with metabolic syndrome (MS).What result of this study add? This study evaluated the link between EC and MS, such as high blood pressure, BMI, fasting blood sugar, triglyceride, Hyper Density Lipoprotein (HDL).What implications are of these findings for clinical practice & further research? Type I EC had and association with MS with obesity is the most potent risk factor. As the prevalence of metabolic syndrome is alarmingly high among adult Malaysians, the incidence of EC is projected to increase in the coming years. Proactive preventative measures and intervention essential for reducing the incidence of endometrial cancers. Future research to clarify the association between metabolic syndrome and endometrial cancer survival and to investigate other lifestyle factors that may affect the prognosis is needed.
  18. Mokhtar NH, Abas A, Razak NA, Hamid MNA, Teong SL
    J Theor Biol, 2017 11 21;433:73-84.
    PMID: 28844907 DOI: 10.1016/j.jtbi.2017.08.016
    Proper design of stent for application at specific aneurysm effect arteries could help to reduce the issues with thrombosis and aneurysm. In this paper, four types of stent configuration namely half-Y (6 mm), half-Y (4 mm), cross-bar, and full-Y configuration will implanted on real 3D artery bifurcation aneurysm effected arteries. Comparisons were then conducted based on the flow patterns after stent placement using both LBM-based solver and PIV experimental findings. According to the data obtained from all 4 stent designs, the flow profiles and the computed velocity from both methods were in agreement with each other. Both methods found that half-Y (6 mm) stent configuration is by far the best configuration in reducing the blood velocity at the vicinity of the aneurysm sac. The analysis also show that the half-Y (6 mm) stent configuration recorded the highest percentage of velocity reduction and managed to substantially reduce the pressure at the bifurcation region. This high flow velocity reduction through the use of half-Y stent could consequently promote the formation of thrombus thereby reducing the risk of rupture in the aneurysm sac.
  19. Razak NA, Hashim S, Mhareb MH, Tamchek N
    Luminescence, 2016 May;31(3):754-9.
    PMID: 26333749 DOI: 10.1002/bio.3020
    Influence of Nd(3+) concentration on the optical and thermoluminescence (TL) properties of melt-annealed synthesized 10 Na2 O: 20 Li2 O: (70-x) B2 O3 : xNd2 O3 , where 0.1≤ x ≤0.7 (LNB) glasses are determined. The absence of sharp peaks in X-ray diffraction patterns confirms the amorphous nature of the prepared glasses. The photoluminescence spectra under 800 nm laser excitations at room temperature exhibit three prominent peaks centred at 538, 603 and 675 nm corresponding to the transitions of (4) G7/2 → (4) I9/2 , [(4) G7/2 → (4) I11/2 , (4) G5/2 → (4) I9/2 ] and [(4) G7/2 → (4) I13/2 , (4) G5/2 → (4) I11/2 ], respectively. The TL glow curve exhibits a prominent peak (Tm ) at 180°C. The best performance of the prepared glass was found at 0.5 mol% of Nd2 O3 . We achieved a good linearity of TL response against dose between 0.5 to 4.0 Gy. The calculated value of the effective atomic number, Zeff , is 7.55 which is nearly tissue equivalent (Zeff = 7.42). These promising features demonstrate the capability of the aforementioned glass to be used as a radiation dosimeter. Copyright © 2015 John Wiley & Sons, Ltd.
  20. Mhareb MH, Hashim S, Ghoshal SK, Alajerami YS, Saleh MA, Razak NA, et al.
    Luminescence, 2015 Dec;30(8):1330-5.
    PMID: 25828828 DOI: 10.1002/bio.2902
    We report the impact of dysprosium (Dy(3+)) dopant and magnesium oxide (MgO) modifier on the thermoluminescent properties of lithium borate (LB) glass via two procedures. The thermoluminescence (TL) glow curves reveal a single prominent peak at 190 °C for 0.5 mol% of Dy(3+). An increase in MgO contents by 10 mol% enhances the TL intensity by a factor of 1.5 times without causing any shift in the maximum temperature. This enhancement is attributed to the occurrence of extra electron traps created via magnesium and the energy transfer to trivalent Dy(3+) ions. Good linearity in the range of 0.01-4 Gy with a linear correlation coefficient of 0.998, fading as low as 21% over a period of 3 months, excellent reproducibility without oven annealing and tissue equivalent effective atomic numbers ~8.71 are achieved. The trap parameters, including geometric factor (μg), activation energy (E) and frequency factor (s) associated with LMB:Dy are also determined. These favorable TL characteristics of prepared glasses may contribute towards the development of Li2O-MgO-B2O3 radiation dosimeters.
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links